塑料注射模具設(shè)計及其熱分析

1、努壤蠼林頤褙觖某柢瀆僦餾耐抒燎鰩扳蔬捆猬飫嬡 蕁斂懣芾勤孀烈梭吾廁滎畢業(yè)設(shè)計(論文)外文資料翻譯蜜瑁衫曄嗪螗岸開毫鳧輸氯恙洹靛舯同瀠縝蹄蹄幸湍殲嚼廊喂祥塵噪俗燎澍系部： 機(jī)械工程系 排探鋪鶼耐赴溪蕁孓戕耿專 業(yè)： 機(jī)械工程及自動化 單毒寐锏啼瀲熊康牝泥銫姓 名： 尢厴庀關(guān)昀礴睥蹲啷岈結(jié)學(xué) 號： 光坊班瞍蘞啾阝闊喀豬酋(用外文寫)籪孟磕甓懇評癩鴿貰瘊聆外文出處： Manufacturing Engineering and 壓慮人哺謄蠻睦蒞癮廉餑 TechnologyMachining 瘙酵苣嗣覡貊蓋褒蠲洧獒附 件： 1.外文資料翻譯譯文；2.外文原文。 狺吭忒螵膝冉訪岙婢廣僨耢粼霧雞耬書浹鑰赫嗓

2、萸拘毓涯允挾宥豁甓鞏莢鵜指導(dǎo)教師評語：紉蜇躪茇糝獪骸芑兆垢娣該外文翻譯語言流暢通順，較準(zhǔn)確完整地翻譯了原文，所翻譯的文章模具設(shè)計原理及成型工藝與夾具設(shè)計原理及加工工藝設(shè)計相類似，與畢業(yè)設(shè)計課題相關(guān)聯(lián)。達(dá)到了本科畢業(yè)外文翻譯的要求。摁盆饑薈嶝頰沾筍祛封軍 簽名： 仆編櫪隘煊舉瀾朕蔽皓磔 年 月 日華甌宗風(fēng)歉瀾蛑垛蕹唏禎注：請將該封面與附件裝訂成冊。冠貢竄岑歿誒充悍跋蹦鏖附件1：外文資料翻譯譯文雛竇曇晁嫜泉廁紅騷蒿渾檐仙陔犬喙湫起瑯氵狼快塑料注射模具設(shè)計及其熱分析跋神骱歸慣夷孔忽側(cè)簀眙往蒙迅衢供袷韶朔霾綣抬材料或熔融塑料在同一溫度同一壓力下同時被送到個模腔對于流道設(shè)計來說是很重要的一點(diǎn)。基于這點(diǎn)，

3、模腔的布局一般都是對稱的。 澧術(shù)洛異褓徇鍋尿搔鋼噥另外，氣孔的設(shè)計也是模具設(shè)計中一個重要的方面。公模板和母模板的配合表面有很高的加工精度以防止注塑時泄露的發(fā)生。但是，這會使空氣被封閉在閉合模腔內(nèi)從而導(dǎo)致短射或使零件不完整。合適起氣孔設(shè)計可以使空氣釋放出來不會出現(xiàn)零件不完整的現(xiàn)象。 挑擾嫻嚌駕燈噼茜鏍蟛荑冷卻系統(tǒng)是沿模腔長度方向在模具上打出的水平孔，只起冷卻作用。在湍流情況下，水線可以充分冷卻模具。圖2顯示了在公模板上氣孔、水線以及模腔的布局。 艙騙椴俱獵砬貓乎循虧曦圖2 在公模板上氣孔、水線以及模腔的布局 仿漣溥肉簸賅魔澄癃宋賓在這個設(shè)計中，脫模系統(tǒng)只有推桿固定板、澆口套和推板。交口套的位于公

4、模的中心，它的作用不僅是將產(chǎn)品固定在合適位置，在開模是還起到將產(chǎn)品拉出模腔的作用。因?yàn)楫a(chǎn)品非常薄，通常為1mm，所以不需要設(shè)計其附加的推桿。模腔里的推桿反而有可能在脫模的時候在零件上推出破孔。 縑水祛傘蔡嗩計枵概稗佴最后，還要根據(jù)材料的收縮率留出足夠的公差補(bǔ)償。 客尤咸朋活膚醮紅華菥韉圖3所示的是用Unigraphics設(shè)計的模具三維模型以及線框模型。 伴鄙讓啵滏幡猿愀孬楦獸圖3 模具的三維實(shí)體模型和線框模型 酯慘賃啊罾懋抒捆廣鏟昀貸少她鹋蚌曉嗒讠壅蕩旒3. 結(jié)果與討論 悴芴菀槐飯牟翰裎思鲆繞3.1. 產(chǎn)品的生產(chǎn)及改良 姣摒裂魈騙芹捩誅炒影窄模具的設(shè)計和制造完成后，試模注塑出來的翹曲試樣會存在

5、很多缺陷。包括短射、噴濺和翹曲。短射的解決可以通過在模腔的角落里銑出附加的氣孔來排出被困的空氣。同時，減小注射壓力可以減小噴濺的發(fā)生。對于翹曲的控制可以通過控制很多因素，例如注射時間、注射溫度和溶料溫度。 鶴被墾覺鋌眸睥粱而噫聞經(jīng)過這些修整之后，模具可以生產(chǎn)出低成本高質(zhì)量的翹曲試樣，這些試樣需要經(jīng)過簡單的拋光處理。圖4顯示的是修整后的模具，加工出附加的排氣孔可避免短射現(xiàn)象的發(fā)生。 辨東糞砹疙艨繾撳輩敘磯圖4 附加氣孔以避免短射 妒行聶?quán)缘本呒薨睬拌?.2. 模具及產(chǎn)品的詳細(xì)分析 鑼偈鵯耥覘貫潑夕炮偎輕模具和試樣都準(zhǔn)備好之后，就可以對其進(jìn)行分析了。在注塑的過程中，210熔融的ABS通過母模上的

6、澆口套直接注入模腔，經(jīng)過冷卻，制件就成型了。制件的生產(chǎn)周期為35s，包括20s的冷卻時間。用來制造模具的材料是AISI 1050碳鋼。表2列出了ABS以及AISI 1050碳鋼的性能。 動囿嫌吵弋樵嚙潤顆跆怒表2 ABS以及AISI 1050碳鋼的性能 森拗鰓痹亨捌裨戛尷閭侃模具，AISI 1050碳鋼 唷靠姝丟敵妍為髀辣琶侑試樣，ABS 盞匣尹蠢冒冰熔憾胗蜊盛密度 7860 kg/m3 懿攙癡奈懨爿燃諒砜叔舐彈性模量 208 GPa 咳焰述酥窩芡孀礫召威拼泊松比 0.297 瑪互困潦儂疰賚煅靼遺定屈服強(qiáng)度 365.4MPa 痞頡泣翹椿伙瘳忐潑耜鄖抗拉強(qiáng)度 636MPa 挺眉裁咼淪冕平垓淀腦疰

7、熱膨脹率 65106 K1 觳揮琨覬朧佃鮑協(xié)皮憚甫電導(dǎo)率 0.135 W/(m K) 襞況躍緗稷患鮮擲退毋缽比熱 1250 J/(kg K) 蚺坡彈標(biāo)蘊(yùn)闥擺閩鶻怯交1050 kg/m3 媯扳各璇晌恬呱越隨圃槧2.519 GPa 琳寡馴樞櫬霞頰飾仕逛迨0.4 涔驪奠育賒駐嘩場篩貨卦65MPa 縫鷸歐玎箢腡蓍艟猝瘧們嗓免諉粱著泰訌丹崾變鄯11.65106 K1 懨狗賈沼亮夫尻邾司淞醵49.4 W/(m K) 弧衣山苣譎圖文升占篥硐477 J/(kg K) 樘螽蒲姻居蜜停瘕扣累闈由于對稱，在注塑過程中只需對公模和母模垂直截面的上半部分進(jìn)行熱分析。圖5所示的是多層模板閉合的熱分析模型。 翕倉渚蚧鞏鋦遺

8、欄畏詐桅建模包括分配各部分的性能以及模型的循環(huán)周期。這樣可以用有限元分析軟件用造型模擬模具模型進(jìn)行分析，還可以繪制時間響應(yīng)曲線顯示再某段時間內(nèi)特定區(qū)域的溫差變化。 裸瀘攫祿摘煩眵獸吹盂簧對試樣的分析可以用LUSAS分析員13.5.版本分析雙向拉伸應(yīng)力。一般只需在試樣的一端施加拉力另一端則固定住，然后慢慢增加拉力一直到達(dá)塑性極限。圖6所示的示分析的加載模型。 臁縈沮蹲銘摩裔耳擘緋捺圖5 熱分析模型 圖6 試樣分析的加載模型 步降每悶冪獨(dú)怠掇耔掏輟3.3. 模具及試樣分析的結(jié)果及討論 廢稚費(fèi)褶的癮搟逕絎糾剪模具分析過程對不同時間段的熱量分布作了觀測。圖7所示是在一個完整的注塑周期中不同時間段的二維

9、等高線熱量分布圖。 摒綿摹漂半跗栓湫終玩外對模具進(jìn)行二維分析后，可繪制出時間響應(yīng)曲線以分析殘余熱應(yīng)力對制件的影響。圖8所示是繪制時間響應(yīng)曲線所選的節(jié)點(diǎn)。 良硝胃菘逮珊崧喚纘栝踅圖917所示的是圖8中各節(jié)點(diǎn)的溫度分布曲線。 子官繼僵弛斥鳘懼肅桐扮圖7 不同時間段的熱量等高線分布圖 竺刨貨婺戇諄囔狳綞逢汰圖8 在制件上為繪制時間響應(yīng)曲線選擇的節(jié)點(diǎn) 圖9 節(jié)點(diǎn)284的溫度分布曲線 淦唰煽跎嗇鋤僮竅箢縶廊從圖917中的溫度分布曲線可以清楚的看出每個節(jié)為曲線圖選擇計畫翻譯經(jīng)歷溫度的增加, 也就是從那對特定的溫度周圍超過溫度比較高的周圍溫度然后在這保持持續(xù)一段特定時間的溫度。這些增加溫度是由溶化塑料的注入

10、產(chǎn)品的型腔所引起的。 縝醞墮佼京瑜莊佳韙栽杠在一段特定時間之后, 溫度更進(jìn)一步增加達(dá)成最高的溫度，然后保持該溫度。這里的溫度增加是由于包裝階段相關(guān)的高壓導(dǎo)致的。這個溫度一直持續(xù)到冷卻階段的開始。計畫翻譯的曲線圖不是平滑適當(dāng)?shù)牡侥禽斎肴芑说某涮钗锫实娜鄙俟δ芩芰虾屠鋬鰟┑睦鋮s比率。繪制的曲線是不平滑的，因?yàn)樽⑷肴廴谒芰系乃俾屎屠鋮s速率是相應(yīng)的。這條曲線僅反應(yīng)了一個周期里可以達(dá)到的最高溫度。 渤綺蛻驚桕掊檀拙榱嚦靛熱殘余應(yīng)力的分析中最關(guān)鍵的階段在冷卻階段。這是因?yàn)槔鋮s階段導(dǎo)致材料冷卻從高溫到玻璃態(tài)轉(zhuǎn)變溫度的低溫。物質(zhì)的不均勻收縮可能產(chǎn)生熱應(yīng)力從而引起翹曲。 佘蟪硤癤嫦倉鰉拖米肯慎圖10 節(jié)點(diǎn)21

11、3的溫度分布曲線 圖11 節(jié)點(diǎn)302的溫度分布曲線 鄢嘉虧肜祠卑戩趣東魂就圖12 節(jié)點(diǎn)290的溫度分布曲線 華胬善貘傲鼻懔嗨頒饣詣剔耪解萊泛靶婢縉鈍骺蚌如圖9-17中所示冷卻階段后的溫度顯示，離水線越近的地方冷卻效果越好，相反則越差。冷卻越快收縮也越大。雖然，節(jié)點(diǎn)284離水線最遠(yuǎn)，卻冷卻得很快，那是因?yàn)闊崃勘会尫诺街車沫h(huán)境中了。 唷霉寵璩另護(hù)沂跗釃冖蠶圖13 節(jié)點(diǎn)278的溫度分布曲線 圖14 節(jié)點(diǎn)1838的溫度分布曲線 藜桃邀守粳背竭卸驕巫戲圖15 節(jié)點(diǎn)1904的溫度分布曲線 圖16 節(jié)點(diǎn)1853的溫度分布曲線 禮家铘錒鄔憩帑能濉攏螗圖17 節(jié)點(diǎn)1866的溫度分布曲線 棘佬咚鲇傍逯薅艸抑誣拽

12、根據(jù)以上所述，水線位于產(chǎn)品型腔的中心引起了中心周圍的溫度高于其他區(qū)域。因此，中心區(qū)域會由于受到收縮力的作用產(chǎn)生更大的收縮從而產(chǎn)生翹曲。然而, 冷卻溫度在不同的節(jié)點(diǎn)處的不同很小，翹曲效果不非常明顯。設(shè)計一個有比較小的殘余熱應(yīng)力作用和一個有效率的冷卻系統(tǒng)的模具對于一個設(shè)計者來說是很重要的。遣廣恢璧受鱟系荊掎帔堡注塑注射成型工藝是一個循環(huán)過程?？煞譃樘盍?、注射、冷卻、脫模四個重要階段。塑料注射成型過程開始于往料斗到注塑機(jī)的加熱或注射系統(tǒng)中填入樹脂和適量的添加劑。灌漿階段就是在注射溫度下用融解的熱塑料注入模腔。模腔被填滿之后，適量的熔融塑料在一個較高的補(bǔ)償壓力下補(bǔ)充塑料凝固引起的收縮。跟著是冷卻階段，

13、將模具冷卻至有足夠的剛度脫出模具。最后是脫模階段，即打開模具然后頂出零件，再合上模具開始下一個循環(huán)。 憲暖索粱苞鋌誼鼷囔摁毽需要注塑成型的塑料產(chǎn)品的設(shè)計和制造與預(yù)期性能是要靠經(jīng)驗(yàn)控制的一個昂貴的過程，包括實(shí)際對封面壓花的修改。在模具設(shè)計之中，設(shè)計模具具體補(bǔ)充幾何，通常在核心邊，包括相當(dāng)復(fù)雜的投射和凹槽。 銼被咱駛旺訶劬抗賂巨臣對于產(chǎn)品分析, 從被實(shí)行開始到分析塑料產(chǎn)品,在產(chǎn)品上不同負(fù)荷因素的狀態(tài)下的應(yīng)力分配情況可以通過觀察生成的二維曲進(jìn)行線分析。 蕆郊孫鮫仡聹瘍犍嶷垓茳分析的時候選擇了一個臨界節(jié)點(diǎn)，即節(jié)點(diǎn)127，這是拉應(yīng)力最大的時候。此時參考負(fù)載應(yīng)力曲線如圖23,它很清楚表明產(chǎn)品在增加拉力負(fù)荷

14、，直到它達(dá)到了23的負(fù)載因數(shù),這意謂產(chǎn)品能抵抗的1150 N的拉力。由圖23可知,對產(chǎn)品的固定端以施加最大應(yīng)力3.27 107 Pa時損壞可能發(fā)生在其附近區(qū)域。 業(yè)愜遲股腐弘熏豕茛蜒蝶4. 結(jié)論 宄牘氦瑪玳溯珍蠃間漿噤經(jīng)過翹曲測試試樣的分析確定影響翹曲的參數(shù)來設(shè)計的模具已經(jīng)使產(chǎn)品質(zhì)量達(dá)到最高。生產(chǎn)測試試樣所需的成本很低而且只需經(jīng)過很少的表面處理。 兩劫竭來恝咯釘餿敝蚺視通過注塑模的熱分析得出殘余熱應(yīng)力對試樣的影響，對加載拉應(yīng)力的分析也可以預(yù)測到翹曲測試試樣所能承受的最大拉力。 仫弦腱幛鱖奩猶靛毗劌鍤猛蟑榕釋悻洎憬釉壽硝淶團(tuán)貶紐近鲼悚焦乍債迸妯附件2：外文原文（復(fù)印件）愜愍飄穿蔚何宄蕉體嫩囁溯膀

15、母緶眨裟諺羌勉綮部Design and thermal analysis of plastic injection mould溷寮鈸喪頹狳副薷攣淥芡磐菏儀鵪豁食序俁疥橘旮It is important that the runner designed distributes material or molten plastic into cavities at the same time under the same pressure and with the same temperature. Due to this, the cavity layout had been designed

16、in symmetrical form. 聳徨箕弊填籠桶凱栗骨髁Another design aspect that is taken into consideration was air vent design. The mating surface between the core plate and the cavity plate has very fine finishing in order to prevent flashing from taking place. However, this can cause air to trap in the cavity when th

17、e mould is closed and cause short shot or incomplete part. Sufficient air vent was designed to ensure that air trap can be released to avoid incomplete part from occurring. 褫寶錛棠毿租茹試斥樾佤The cooling system was drilled along the length of the cavities and was located horizontally to the mould to allow e

18、ven cooling. These cooling channels were drilled on both cavity and core plates. The cooling channels provided sufficient cooling of the mould in the case of turbulent flow. Fig. 2 shows cavity layout with air vents and cooling channels on core plate. 臉刈宸蚓莓概翁鑭勢顴末晶杲泵替梏掄諏諫捱鑼耄Fig. 2. Cavity layout with

19、 air vents and cooling channels. 跛筏撣乇公顙笞嶝玫轡芬In this mould design, the ejection system only consists of the ejector retainer plate, sprue puller and also the ejector plate. The sprue puller located at the center of core plate not only functions as the puller to hold the product in position when the m

20、ould is opened but it also acts as ejector to push the product out of the mould during ejection stage. No additional ejector is used or located at product cavities because the product produced is very thin, i.e. 1 mm. Additional ejector in the product cavity area might create hole and damage to the

21、product during ejection. 焙川揖于瀅袍皮逮墊嗶止Finally, enough tolerance of dimensions is given consideration to compensate for shrinkage of materials. 疾蠹櫸戮誶新純嘆蜂含蘆Fig. 3 shows 3D solid modeling as well as the wire frame modeling of the mould developed using Unigraphics. 筮牙蚺吖美滄用詞過坡屏Fig. 3. 3D solid modeling and

22、 wireframe modeling of the mould. 撮纂江鏷稃鄄戊忤記苣黍祀癀楷吩覃耀灼膿麴苒嗜壢沿賅峽遲場沃狻搏掂狴楔舒輛崮獍迅鄧買鋁倉蘢3. Results and discussion 死鵜僵榭劂急苘爽燧墟病3.1. Results of product production and modification 鎵引蔸婪嚎嫩鷥旰敏薌夷From the mould designed and fabricated, the warpage testing specimens produced have some defects during trial run. The def

23、ects are short shot, flashing and warpage. The short shot is subsequently eliminated by milling of additional air vents at corners of the cavities to allow air trapped to escape. Meanwhile, flashing was reduced by reducing the packing pressure of the machine. Warpage can be controlled by controlling

24、 various parameters such as the injection time, injection temperature and melting temperature. 柜溧橙腮曷罰回蛺酯輞畸After these modifications, the mould produced high quality warpage testing specimen with low cost and required little finishing by de-gating. Fig. 4 shows modifications of the mould, which is ma

25、chining of extra air vents that can eliminate short shot. 鹋挺睦蒜叩黿浯評欒瘙益Fig. 4. Extra air vents to avoid short shot. 鞲柏愛沾炻餛醬潦令防鈣3.2. Detail analysis of mould and product 庵蜜代蟮弟遛劭姥惰犧柒After the mould and products were developed, the analysis of mould and the product was carried out. In the plastic injecti

26、on moulding process, molten ABS at 210 C is injected into the mould through the sprue bushing on the cavity plate and directed into the product cavity. After cooling takes place, the product is formed. One cycle of the product takes about 35 s including 20 s of cooling time. 吶鐸撣狡嘈緝欠鎧花郫斥The material

27、used for producing warpage testing specimen was ABS and the injection temperature, time and pressure were 210 C, 3 s and 60MPa respectively. The material selected for the mould was AISI 1050 carbon steel. Properties of these materials were important in determining temperature distribution in the mou

28、ld carried out using finite element analysis. Table 2 shows the properties for ABS and AISI 1050 carbon steel. 肢裝鋱娟鯀蹴遣揆萃共掘Table 2 猓餉崩綆軔褪鼻檜摜禹卸Material properties for mould and product 苛受卉扁變墁爨瞀恰哚轡The critical part of analysis for mould is on the cavity and core plate because these are the place where

29、the product is formed. Therefore, thermal analysis to study the temperature distribution and temperature at through different times are performed using commercial finite element analysis software called LUSAS Analyst, Version 13.5. A two-dimensional (2D) thermal analysis is carried out for to study

30、the effect of thermal residual stress on the mould at different regions. 銨蠔魄褻讜填碑錆孱給鮚Due to symmetry, the thermal analysis was performed by modeling only the top half of the vertical cross section or side view of both the cavity and core plate that were clamped together during injection. Fig. 5 shows

31、 the model of thermal analysis analyzed with irregular meshing. 效從轡匪肌灬陸庇嬗誅朔Modeling for the model also involves assigning properties and process or cycle time to the model. This allowed the finite element solver to analyze the mould modeled and plot time response graphs to show temperature variation

32、 over a certain duration and at different regions. 餅昶夭務(wù)蕉綏函捌汛稹蹊For the product analysis, a two dimensional tensile stress analysis was carried using LUSAS Analyst, Version 13.5. Basically the product was loaded in tension on one end while the other end is clamped. Load increments were applied until t

33、he model reaches plasticity. Fig. 6 shows loaded model of the analysis. 桓諞岵爸顯螄牘讖輩燒豚 婆諒嚙炷憮眷崮彎本優(yōu)顴Fig. 5. Model for thermal analysis. Fig. 6. Loaded model for analysis of product. 添趴揮蜊粉涕圾炬牯儂躁鑼么詔吹道影祖鈄墾磴3.3. Result and discussion for mould and product analysis 蛛螈仄鐨凱遞觶旬溯昀漚For mould analysis, the thermal d

34、istribution at different time intervals was observed. Fig. 7 shows the 2D analysis contour plots of thermal or heat distribution at different timeintervals in one complete cycle of plastic injection molding. 跌棰令縹芮椹諳撅杰討鱔Fig. 7. Contour plots of heat distribution at different time intervals. 改去衫踹秕猞摔伽錦

35、俘剴For the 2D analysis of the mould, time response graphs are plotted to analyze the effect of thermal residual stress on the products. Fig. 8 shows nodes selected for plotting time response graphs. 葵柢燾區(qū)墟疃耐昆斬苔姹Figs. 917 show temperature distribution curves for different nodes as indicated in Fig. 8.

36、蓑錆宸艸苊醭熬嵌槽振橛From the temperature distribution graphs plotted in Figs. 917, it is clear that every node selected for the graph plotted experiencing increased in temperature, i.e. from the ambient temperature to a certain temperature higher than the ambient temperature and then remained constant at thi

37、s temperature for a certain period of time. This increase in temperature was caused by the injection of molten plastic into the cavity of the product. 諷嵴納瑟淹醢洞夢藏且吮After a certain period of time, the temperature is then further increased to achieve the highest temperature and remained constant at that

38、 temperature. Increase in temperature was due to packing stages that involved high pressure, which caused the temperature to increase. This temperature remains constant until the cooling stage starts, which causes reduction in mould temperature to a lower value and remains at this value. The graphs

39、plotted were not smooth due to the absence of function of inputting filling rate of the molten plastic as well as the cooling rate of the coolant. The graphs plotted only show maximum value of temperature that can be achieved in the cycle. 廟酢拆柁唿阜藶然虧雇The most critical stage in the thermal residual st

40、ress analysis is during the cooling stage. This is because the cooling stage causes the material to cool from above to below the glass transition temperature. The material experiences differential shrinkage that causes thermal stress that might result in warpage. 眩曄嗝裘唱榱磯蜉芰醴透From the temperature afte

41、r the cooling stage as shown in Figs. 917, it is clear that the area (node) located near the cooling channel experienced more cooling effect due to further decreasing in temperature and the region away from the cooling channel experienced less cooling effect. More cooling effect with quite fast cool

42、ing rate means more shrinkage is occurring at the region. However, the farthest region , Node 284 experience more cooling although far away from cooling channel due to heat loss to environment. 孺拜黧乓戚楂鴟鰒葉凈觴圖哳桅襠缽氈躺錨辰吉豸Fig. 8. Selected nodals near product region for time response graph plots. 晁驍芒鍇遢眨篆亭郗

43、闡胎Fig. 9. Temperature distribution graph for Node 284. 崎釋累臁綆耄蓮蹦銬撓瞬Fig. 10. Temperature distribution graph for Node 213. Fig. 11. Temperature distribution graph for Node 302. 觚澗咎燎啊婺蔦將凸煉站騁純啕闕淅芑粒霈蝦醑璁Fig. 12. Temperature distribution graph for Node 290. Fig. 13. Temperature distribution graph for Node 2

44、78. 建懷唳芝哄蛔蘚扶萍坪姥Fig. 14. Temperature distribution graph for Node 1838. Fig. 15. Temperature distribution graph for Node 1904. 錐惠冉樟邏嘿紈璃劁聞雅Fig. 16. Temperature distribution graph for Node 1853. Fig. 17. Temperature distribution graph for Node 1866. 久休忡的沽莜鑿是勒讞傘旅焚線箜醋潢染厄鏍皰婧As a result, the cooling channel

45、 located at the center of the product cavity caused the temperature difference around the middle of the part higher than other locations. Compressive stress was developed at the middle area of the part due to more shrinkage and caused warpage due to uneven shrinkage that happened. However, the tempe

46、rature differences after cooling for different nodes are small and the warpage effect is not very significant. It is important for a designer to design a mould that has less thermal residual stress effect with efficient cooling system. 摯鈰襯讀絆鏤綏寥硐嘲秋For the product analysis, from the steps being carrie

47、d out to analyze the plastic injection product, the stress distribution on product at different load factor is observed in the two dimensional analysis. 哚軎嘸蕖肄窠蠊春鹺母閶A critical point, Node 127, where the product experiences maximum tensile stress was selected for analysis. The plastic injection moldin

48、g process is a cyclic process. There are four significant stages in the process. These stages are filling, packing, cooling and ejection. 桀睛愛勃僨瓷涕朧謔橢慊The plastic injection molding process begins with feeding the resin and the appropriate additives from the hopper to the heating/injection system of th

49、e injection plastic injection molding machine . This is the “filling stage” in which the mould cavity is filled with hot polymer melt at injection temperature. After the cavity is filled, in the “packing stage”, additional polymer melt is packed into the cavity at a higher pressure to compensate the

50、 expected shrinkage as the polymer solidifies. This is followed by “cooling stage” where the mould is cooled until the part is sufficiently rigid to be ejected. The last step is the “ejection stage” in which the mould is opened and the part is ejected, after which the mould is closed again to begin

51、the next cycle . 穗蓋仉繼楨嘌麒鱔襦殫樵The design and manufacture of injection molded polymeric parts with desired properties is a costly process dominated by empiricism, including the repeated modification of actual tooling. Among the task of mould design, designing the mould specific supplementary geometry,

52、usually on the core side, is quite complicated by the inclusion of projection and depression . 顫唉烯編蓁燙騾瞌芯奎蘗裾鬮礅闌噢徼牌依纓咒獐From the load case versus stress curves at this point plotted in Fig. 23, it is clear that the product experiencing increased in tensile load until it reached the load factor of 23, w

53、hich is 1150 N. This means that the product can withstand tensile load until 1150 N. Load higher than this value causes failure to the product. Based on Fig. 23, the failure is likely to occur at the region near to the fixed end of the product with maximum stress of 3.27107 Pa. 悖嚕帔舟氽姒剩潰渠生滋4、Conclusi

54、on卑狼斑鐺雛攵臉怖嫜懿怪The product stress analysis reveals very limited information since the product produced was for warpage testing purposes and had no relation with tensile loading analysis. 濾嗜祟弓笥椐童無漫璺氬In future, however, it is suggested that the product service condition should be determined so that furt

55、her analysis may be carried out for other behaviors under various other loading. that affect warpage. The testing specimen was produced atlow cost and involves only little finishing that is de-gating. 瓊遭摒鏑猾便蹼雯堡唱蕹The thermal analysis of plastic injection mould has provided an understanding of the eff

56、ect of thermal residual stress on deformed shape of the specimen and the tensile stress analysis of product managed to predict the tensile load that the warpage testing specimen can withstand before experiencing failure. 讜撬戡厭嗆萌鎬讎逄洗疽煜寰杯造由氕猿蛙吳皎弟沒栽梳亮殲壇乎徽榮骺芮栩問瞳瀉鯉緣螫悃疣婺呷國舯踉連糯穸垂縫喧奔敦艫谫訶葒耄呈璧喇豐捍鉸支緣鰭插伎酰旃猻兆桂滲郴氟

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